1. Field of the Invention
The present invention relates to a display apparatus, and, more particularly to a display apparatus that uses a polymer dispersed liquid crystal and a manufacturing method thereof.
2. Description of the Related Art
As liquid crystal display apparatus that uses a polymer dispersed liquid crystal does not utilize a polarizing plate, the apparatus has a characteristic in that the display image of the apparatus is bright. Therefore, it is used as a display apparatus in many devices or apparatuses. This polymer dispersed liquid crystal display apparatus irradiates a polymer material (hereinafter, “monomer”) with an ultraviolet ray, the polymer material is photo-polymerized, cross-linked, polymerized, and is used by the display apparatus. Further, in an active matrix type display apparatus that uses such a polymer dispersed liquid crystal, a light shielding film, a wiring electrode, or a reflective layer is arranged on a substrate to display an image. Since the light shielding film of a black matrix, or the wiring electrode and the reflection film, both of which have reflective properties, blocks an ultraviolet ray when the monomer is irradiated, a problem of unpolymerization occurs in the monomer.
As a conventional technology that eliminates the occurrence of unpolymerization of the monomer, there is a technology disclosed in the following patent document 1.
One of technologies disclosed in patent document 1 provides a structure in which a light shielding layer is provided on an opposed substrate facing an array substrate having TFT elements and data lines provided thereon in parallel with the data lines so as to prevent light from being transmitted through the TFT elements and prevent light from being transmitted through positions on the opposed substrate corresponding to gaps between the data lines and pixel electrodes, and a light shielding area of the light shielding layer is reduced so that a monomer can be uniformly irradiated with an ultraviolet ray.
patent document 1: Japanese Patent Application Laid-Open Publication No. H8-101405
patent document 2: Japanese Patent Application Laid-Open Publication No. 2003-177427
A liquid crystal display apparatus generally has a configuration where a frame-like light shielding unit called a corner bead is provided in a peripheral region outside a display region where an image is displayed to prevent unnecessary light rays from leaking or prevent frame-like unnecessary light from leaking, thereby obtaining excellent display. The technology disclosed in patent document 1 concerns a configuration that eliminates unpolymerization of a monomer in a display region, and does not refer to the light shielding unit called a corner bead.
In a liquid crystal display apparatus that has a frame-like light shielding unit called a corner bead, an ultraviolet ray is prevented from being transmitted through the light shielding unit, and hence an unpolymerized part is produced in a monomer that is present in the light shielding unit. Further, such a quality phenomenon as depicted in FIG. 20 occurs. FIG. 20 is a plan view of the quality phenomenon in the liquid crystal display apparatus, and this apparatus has a problem that an unpolymerized monomer that is present in a light shielding unit 202 is exuded to a display region 201 for a long time such that an exuded portion 203 appears and this results in display unevenness of a display image. Furthermore, it also has a problem that a display quality is deteriorated.
In a method of manufacturing a liquid crystal display apparatus, a method of applying an ultraviolet ray from a display image visible side or a method of applying an ultraviolet ray from an opposite side of the visible side, i.e., a rear surface side of the liquid crystal display apparatus can be adopted, for example. However, a structure where a reflection film or a wiring electrode having light shielding properties is provided on a substrate facing a substrate having a light shielding unit called a corner bead provided thereon has a problem in that the reflection film or the wiring electrode is obstructive such that a monomer is not uniformly irradiated with the ultraviolet ray even if the method of applying the ultraviolet ray from the rear surface side of the liquid crystal display apparatus is carried out. The monomer at a position where it is not subject to irradiation with the ultraviolet ray remains in an unpolymerized state, the unpolymerized material exudes to a display region with time, and such a phenomenon as depicted in FIG. 20 arises.
In view of the problems, an object of the present invention is to provide a structure of a liquid crystal display apparatus that enables sufficient photo polymerization of a monomer that is present in both a display region and a light shielding region even if an ultraviolet ray is applied from a display image visible side or an opposite rear surface side of the liquid crystal display apparatus, thereby polymerizing the monomer. Additionally, another object of the present invention is to provide a manufacturing method of polymerizing a monomer that is present in both a display region and a light shielding region by a single ultraviolet ray applying operation.